At the same time that the Birds volumes were passing through the press, Buffon also issued periodically seven volumes of a supplement (1774-1789), the last appearing posthumously under the editorship of Count Lacepede. This consisted of an olla podrida of all sorts of papers, such as would have won the heart of Charles Godfrey Leland. The nature of the hotchpotch will be understood from a recital of some of its contents, in their chronological order. It opened with an introduction to the history of minerals, partly theoretical (concerning light, heat, fire, air, water, earth, and the law of attraction), and partly experimental (body heat, heat in minerals, the nature of platinum, the ductility of iron). Then were discussed incandescence, fusion, ships' guns, the strength and resistance of wood, the preservation of forests and reafforestation, the cooling of the earth, the temperature of planets, additional observations on quadrupeds already described, accounts of animals not noticed before, such as the tapir, quagga, gnu, nylghau, many antelopes, the vicuna, Cape ant-eater, star-nosed mole, sea-lion, and others; the probabilities of life (a subject on which the author plumed himself), and his essay on the Epochs of Nature. Nor did these concurrent series of books exhaust his boundless energy and ingenuity, for in the five years preceding his death (1783-1788), he produced his "Natural History of Minerals" in five volumes, the last of which was mainly occupied with electricity, magnetism, and the loadstone. It is true that the researches of modern chemists have wrought havoc with Buffon's work in this field; but this was his misfortune rather than his fault, and leaves untouched the quantity of his output. Buffon invoked the aid of the artist almost from the first, and his "Natural History" is illustrated by hundreds of full-page copper-plate engravings, and embellished with numerous elegant headpiece designs. The figures of the animals are mostly admirable examples of portraiture, though the classical backgrounds lend a touch of the grotesque to many of the compositions. Illustrations of anatomy, physiology, and other features of a technical character are to be numbered by the score, and are, of course, indispensable in such a work. The _editio princeps_ is cherished by collectors because of the 1,008 coloured plates ("Planches Enluminees") in folio, the text itself being in quarto, by the younger Daubenton, whose work was spiritedly engraved by Martinet. Apparently anxious to illustrate one section exhaustively rather than several sections in a fragmentary manner, the artist devoted himself chiefly to the birds, which monopolise probably nine-tenths of the plates, and to which he may also have been attracted by their gorgeous plumages.